1. Field of the Invention
The present invention relates to a disk device for recording data onto a disk in accordance with a predetermined layout containing a footer portion.
2. Description of the Related Art
Techniques on the CD-R (compact disk recordable) disk having data stored thereon which can be read out by a CD drive or a CD-ROM drive, are under lively development.
Japanese Patent Examined Publication No. Hei. 6-101121, entitled "Optical Disk Device and Optical Disk", discloses such a technique that when a tracking error occurs during the writing of data onto a CD-R disk, an optical head is returned to the error generating track, and then the writing operation starts again to record data continuously on the optical disk.
Another technique is disclosed in Japanese Patent Unexamined Publication No. Hei. 5-303743, entitled "Playback-End Control Method for an Optical Disk Playback Device". When a tracking error occurs during the reading of data from a CD-R disk, which is under writing and not yet finalized, by a CD drive or a CD-ROM drive, the technique reads out data from a track located at a position radially outwardly counted from the error generating track by a predetermined number of tracks, and judges as to whether or not it is located at the end of the program area, whereby the reading of data at the end of the program area is smoothly ended.
The method of recording data onto the CD-R disk is roughly categorized into four methods; 1) a disk-at-once recording method, 2) a track-at-once recording method, 3) a packet-writing recording method, and 4) a multi-session recording method. Sometimes, some of those recording methods are combined in use.
In the disk-at-once recording method, a record signal is ceaselessly applied throughout a data recording process from a record start to a record end. The record signal is applied in the order from a read-in (representative of a start time (start address) and an end time (end address) of the track, a program (data to be recorded) and a read-out. The disk-at-once recording method enables one track to be formed on one disk.
In the track-at-once recording method, the record signal is applied plural times or for each of the data recording operations. This recording method allows a plural number of tracks to exist on a single disk, and programs can be additionally recorded onto the disk so long as the free memory area is left in the disk. The recording method manages the addresses of the tracks to be subjected to additional recording, by use of a PMA (program memory area), which is formed on the disk in advance, for temporarily storing address information of the respective tracks. In the finalizing process, the stored information is readout of the PMA to form retrieval information called TOC (table of contents), and the recording of a read-in area and then a read-out area is performed. Thus, the record signal is applied in the order of the program, the read-in and the read-out.
The packet-writing recording method eases the limitations on the recording unit of the track-at-once recording method. The data unit lower in rank than the track, i.e., the packet, is used for the additional recording of data. In the recording method, a plurality of packets may be stored in one track.
In the multi-session recording method, the recording of the read-in and read-out areas follows the recording of the program area. Data may be additionally recorded on the disk so long as the free recording area is left in the disk. That is, a plurality of read-in areas and read-out areas may exist on a signal disk.
An operation for additionally writing data onto a single disk by the track-at-once or packet-writing recording method will now be described.
An NWA (next writable area) representative of the next writing address is stored in the PMA (program memory area). The NWA is recorded into the PMA every time the recording to the track is completed (closed). The track-at-once recording method reads out the NWA, and sets up record start addresses of the second and subsequent recording operations (second and subsequent tracks).
In the packet-writing recording method, there is a case that the NWA is invalid since the track recording is not always completed in the previous recording operation.
In the packet-writing recording method, a LINK region is recorded in the trailing end of the packet by a series of procedural steps for recording one packet. The LINK region is used as a margin between the present packet and the next packet to subsequently be recorded.
The LINK region ranging from the readout NWA to the maximum read-out start time of the disk is searched by the binary search method. When the LINK region is not detected, the NWA is set as a record start address. When it is detected, its address is set as the record start address.
The thus set record start address is stored in the work memory of the CD-R drive while the disk is set in the CD-R drive, and is updated with the additional recording of the packet.
When the disk is discharged out of the CD-R drive, the record start address is erased from the work memory. Therefore, when the additional recording of data onto the disk is performed by the packet-writing recording method, the record start address is set up by the above procedure every time the disk is loaded into the disk drive.
Incidentally, the recording characteristic of the CD-R disk is not standardized, viz., it is different for each maker. Further, the conventional CD-R drive does not perform a verifying operation, viz., an inspection operation by comparing the recorded data with the input data to check as to if the input data has been correctly recorded.
When data is recorded onto a disk manufactured by a certain maker, it sometimes happens that data once recorded onto the disk is not recorded therein actually. In this case, when the user reads out data from the disk onto which he recorded the data, a read error occurs, and he knows his recording failure from the read error.